Probe tripped during non-probe move
- mc_cubus
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22 May 2025 15:20 #328920
by mc_cubus
Probe tripped during non-probe move was created by mc_cubus
Hi everyone,
I am pretty new to LinuxCNC and currently working on a setup where a light distance sensor is mounted on a XYZ stage. My goal is to approach an object along z-axis until the sensor reading enters a defined window (26 – 27 mm) and then scan the object along the x-axis, stopping the moment the sensor reading exits that same window.
My current approach was to use probe mechanism with G.38 moves.
The .hal file:
The G-code:
When running the G-code, the probing along Z-axis works just fine and the movement stops the moment we enter the window. When probing along X-Axis starts, it moves for just a tiny bit (~0.2s) and then throws an error: Probe tripped during non-probe move.
The motion.motion-type has value 5 (which is Probing) during both G38 movements, so I don't know where the error comes from.
I'd greatly appreciate any insights into this issue!
Thanks in advance.
I am pretty new to LinuxCNC and currently working on a setup where a light distance sensor is mounted on a XYZ stage. My goal is to approach an object along z-axis until the sensor reading enters a defined window (26 – 27 mm) and then scan the object along the x-axis, stopping the moment the sensor reading exits that same window.
My current approach was to use probe mechanism with G.38 moves.
The .hal file:
# — threshold generator at 26.5 mm (window center) —
loadrt constant count=1
addf constant.0 servo-thread
setp constant.0.value 26.5
# — “near” comparator: output HIGH when |sensor-mm – 26.5| ≤ 0.5 —
loadrt near count=1
addf near.0 servo-thread
setp near.0.difference 0.5
# — feed the threshold and the actual distance into near.0 —
net ref-26p5 constant.0.out near.0.in1
net sensor-mm scale.0.out near.0.in2
# map the “in-window” bit to the probe input
net in-window near.0.out motion.probe-inputThe G-code:
(Move to initial coordinates before probing)
G21
G90
G1 X357 Y31 Z-118 F4800
(Z-approach – stops instantly on entering 26…27 mm)
F600
G38.3 Z-190 F600 ; probe toward, stop on motion.probe-input=1 (no error)
(Dwell 1 s)
G4 P1
(X-scan – stops instantly on exiting 26…27 mm)
F600
G38.5 X300 F600 ; probe away, stop on motion.probe-input=0 (error)
M2 When running the G-code, the probing along Z-axis works just fine and the movement stops the moment we enter the window. When probing along X-Axis starts, it moves for just a tiny bit (~0.2s) and then throws an error: Probe tripped during non-probe move.
The motion.motion-type has value 5 (which is Probing) during both G38 movements, so I don't know where the error comes from.
I'd greatly appreciate any insights into this issue!
Thanks in advance.
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- andypugh
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23 May 2025 19:25 #329003
by andypugh
Replied by andypugh on topic Probe tripped during non-probe move
You are right, this does seem odd.
It might help to log the motion type and the probe input in Halscope, to see if there is some dither in the probe input. Is the stated 0.2s enough time for the target to leave the sense area?
If a couple of ms delay is acceptable then you could potentially add a software debounce to the probe input signal, if noise on the input is the problem.
It might help to log the motion type and the probe input in Halscope, to see if there is some dither in the probe input. Is the stated 0.2s enough time for the target to leave the sense area?
If a couple of ms delay is acceptable then you could potentially add a software debounce to the probe input signal, if noise on the input is the problem.
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